Evidence Stacks Up for Icy Geysers Erupting on Europa

Possible water plumes could give researchers a way to study Jupiter’s moon without drilling

Hubble Directly Images Possible Plumes on Europa

Jupiter’s moon Europa has long been a tantalizing topic of study for scientists looking to learn more about other satellites. For years, planetary researchers have suspected that the moon might hide an ocean of salty, liquid water hidden miles beneath its icy surface. Now, thanks to the Hubble Telescope, NASA researchers have found more evidence suggesting Europa has geysers of liquid water shooting out into space.

The prospect of Europa hiding an ocean of liquid water has intrigued scientists for years, partly because it could make the moon a likely source of some kind of extraterrestrial life—though it would probably be more along the lines of bacteria than space whales. While this latest announcement had nothing to do aliens, it did provide more evidence for Europa having some interesting features just out of sight, Rachel Feltman reports for the Washington Post.

"On Earth, life is found wherever there is energy, water, and nutrients. So we have a special interest in any place that might possess those characteristics. And Europa might be such a place," Paul Hertz, director of NASA’s Astrophysics Division in Washington, D.C. tells Nell Greenfieldboyce for NPR.

Back in 2012, scientists studying data from the Hubble Telescope noticed evidence of water vapor in the atmosphere above Europa’s south pole. Considering researchers have previously spotted evidence of salt water trickling up to the moon’s surface, they figured that the most likely source was a massive geyser of liquid water spurting from below the mile-thick ice, Alan Yuhas reports for The Guardian. That event, however, was the only one researchers had managed to spot—until now, that is.

The new data, which is scheduled to be published in the Astrophysical Journal, was analyzed using the same techniques that astronomers use to study the atmospheres of distant planets. By watching a planet (or in this case, moon) as it passes in front of a nearby bright object, like a star, they can detect whether it has an atmosphere by seeing if it blocks any of that starlight, Feltman reports. When Sparks and his team analyzed more Hubble data, they discovered traces of several massive plumes of water erupting from the moon’s surface over the course of 15 months.

“If plumes exist, this is an exciting find,” Sparks tells Yuhas. “It means we may be able to explore that ocean, that ocean of Europa, and for organic chemicals. It would allow us to search for signs of life without having to drill through miles of ice.” Researchers could grab samples by a flyby, similar to Cassini's recent plunge in the the geysers of Enceladus

But there is a lot more research that needs to be done before the scientists can confirm that the find is, in fact, a giant geyser. The Hubble has been orbiting the Earth for 26 years now, and while Europa hangs out relatively nearby, this research pushed the limits of the space telescope’s capabilities. When its successor, the James Webb Space Telescope, is launched in 2018, it may be able to help paint a clearer picture of any possible waterworks on Europa’s surface, Feltman reports.

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